Generation of Ortho Photo and Contours by Using High Resolution Satellite Data

Transcription

1 International Journal of Engineering and Technical Research (IJETR) Generation of Ortho Photo and Contours by Using High Resolution Satellite Data Dr. S.S.Manugula, Mr. Aavula Siva Sai Kumar, Mr. B. Harish Goud, Mr.Aakula Rakesh Abstract The availability of stereo data from satellite significantly changed the way in which satellite images may be used. Presently, satellite images can be used for applications in which only aerial photographs were used previously. One of the most important applications of satellite stereo data is generation of Digital Terrain Model mission planned satellites like QB, GeoEye and Cartosat which provide the metric quality data. The study area is located in Dehradun. The input data used is cartosat-1 PAN (Stereo image) with resolution of 2.5 m is used in this work to generate a model, ie a 3D stereo view to generate Orthophoto and contours. A suitable DEM must be obtained to provide a vertical datum for an Orthophoto. Some projects may allow inclusion of a DEM for the project area that was developed from other imagery. However, most large-scale ortho-photo projects require a DEM to be developed from the new imagery. This will insure and improve the accuracy of the image rectification. The final phase of the Orthophoto process is the merger of the digital image and the DEM along with corrections in pixel intensity throughout the image. Software, used to merge the digital raster image with the DEM, makes adjustments in the horizontal location of pixels based upon their proximity to DEM points. This process removes the errors due to displacement and produces an image that is orthogonally accurate. Contours are generated with an interval of 10 m and it is exported in the shape file so that the slope can be easily identified for future assessment. Conventional aerial triangulation is reviewed. This review encompasses various mathematical models, self-calibration technique, additional parameters, and the associated mathematical models. Mission planned satellites like IKONOS, QB and Cartosat provide the metric quality data. In this research work, it is proposed to use high resolution satellite stereo data i.e. GeoEye-1 for creating the block setup and AT. Index Terms Aerial Triangulation, DEM, Orthophoto, QB, GeoEye and Cartosat, Contour I. INTRODUCTION An orthophoto or orthoimage is a photograph showing images of objects in their true orthographic positions. Dr. S.S Manugula, Professor in GNITC, has B.Tech, Dy. General Manager& Head of GIS department and also holds the credit of gaining global exposure by working in Abu-Dhabi (UAE) Mr. A Siva Sai Kumar, Student of GNITC, Final year B.Tech Civil Engineering, International Geospatial Form and also achieved 2nd Prize in paper/ project presentations in GNI colleges. Mr. B. Harish Goud, Student of GNITC, Final year B.Tech Civil Engineering., participated in Institute of Engineers, International Geospatial Form and also achieved 2nd Prize in paper/ project presentations in GNI colleges Mr. A. Rakesh, Student of GNITC, Final year B.Tech Civil Engineering. He participated in Institute of Engineers, International Geospatial Form and also achieved Prize in paper/ project presentations in various colleges Orthophotos are therefore geometrically equivalent to conventional line and symbol planimetric maps, which also show true orthographic positions of objects. The major difference between an orthoimage and a map is that an orthoimage is composed of images of features, whereas maps utilize lines and symbols plotted to scale to depict features. Because they are planimetrically correct, orthoimage can be used as maps for making corrections for making direct measurements of distances, angles, positions, and areas without making corrections for image displacements. A. Orthorectification : The ortho rectification process takes the raw digital imagery and applies a DEM and triangulation results to create an image or photograph with an orthographic projection is one for which every point looks as if an observer were looking straight down at it, along a line of sight that is orthogonal (perpendicular) to the Earth. Relief displacement is corrected by taking each pixel of a DEM and finding the equivalent position in the satellite or aerial image. A brightness value is determined for this location based on resampling of the surrounding pixels. The brightness value, elevation, and exterior orientation information are used to calculate the equivalent location in the orthoimage file, Yang, X [13]. In practice, the constant scale of an Orthoimages means that the distance measured between any two points in the image can be converted to its corresponding distance on the ground by multiplying by a single scale factor. As a result, an orthorectified image can be used in a Geographic Information System (GIS) as a base map layer over which vector layers, such as road networks, can be laid. Another related advantage of the orthoimage is that many Orthoimages can be mosaic together to form a seamless image map covering large areas. A. Objective II. OBJECTIVE AND STUDY AREA The main objective of the project is to generate i) Create 3D-Stereovision by AT ii) Orthophoto iii) Contour generation B. Study Area The Study area is Dehra Dun which is the capital city of the state of Uttarakhand in the northern part of India. Located in the Kadhauli region, it lies 236 kilometers (147 mi) north of India's capital New Delhi and is one of the "Counter Magnets" of the National Capital Region (NCR) being developed as an alternative Centre of growth to help ease the migration and population explosion in the Delhi metropolitan area and creation highways to establish a smart city at Dehradun. 14

2 Generation of Ortho Photo and Contours by Using High Resolution Satellite Data Graphic Status. We can also view Project Graphic Status Window-a display whose contents are controlled with the tools in the right side of the viewer. Now click on new file icon to create a new block file. Fig-1 Meta Data AOI:-The extent of study area lies between longitude 77 46' to E and latitude 30 27' to N. Area_ (AOI): Sq. mi Fig-3 Block File Creation III. METHODOLOGY Generation of DEM Contours and Ortho image from high resolution data. Once the proper selection is made the stereo pair has to be oriented/ triangulated using sensor parameters and ground control points to generate exterior orientations. In this project work Digital photogrammetric techniques has proposed to use for generation of DEM. Then the Orthoimage and Contours is generated from the DEM. A flowchart of methodology for Generation of DEM and Orthoimage is shown in the following Figure 2. Fig-4 Adding Images Fig-2 Flow chart Fig-5 Point Measurement Tool A. Process Set up Block files have the.blk extension. A block file may be made up of only one image, a strip of images that are adjacent to one another, or several strips of imagery. The.blk file is a binary file. In it all the information associated with the block including imagery locations, camera information, fiducial mark measurements, GCP measurements etc are stored. For creating a new project we click on the LPS icon pan. The LPS project manager viewer is opened. In the viewer we can access tools using toolbar. There is a Block Project tree view; we can make selections here to view them in the Project IV. RESULT ANALYSIS The results for each iteration of processing are calculated once the triangulation has been performed. This value is computed based on the image coordinate residuals for that particular iteration of processing. The computed standard error for each iteration accumulates the effect of each image coordinate residual to provide a global indicator of quality. The lower the standard error, the better the solution. Adjustment Report With OrthoBASE Output image units: pixels 15

3 Output ground units: degrees Output z units: meters Calculated ground x, y and z coordinates: degrees meters type pid ground_x ground_y ground_z gcp gcp gcp gcp gcp chk chk chk chk tie tie tie tie tie tie tie tie tie tie tie tie tie tie tie tie Control and check point residuals:degrees meters type pid residual_x residual_y residual_z gcp gcp gcp gcp gcp chk chk chk chk Image point residuals: imgid pid residual_x residual_y International Journal of Engineering and Technical Research (IJETR) Ax= Ay= Mx= My= Ax= Ay= Mx= My= Total unit weight RMSE = Image accuracy for control and check points for each scene: image id 1: pid type image_x image_y residual_x residual_y 4 gcp gcp gcp gcp gcp chk chk chk chk GCPs: x: y: Total: CHKs: x: y: Total: image id 2: pid type image_x image_y residual_x residual_y 4 gcp gcp gcp gcp

4 Generation of Ortho Photo and Contours by Using High Resolution Satellite Data 22 gcp chk chk chk chk Fig-7 Created 3D-Stereovision by AT B. Ortho Resampling 5 GCPs: x: y: Total: CHKs: x: y: Total: Summary RMSE for GCPs and CHKs (number of observations in parenthesis): Control Check Ground X: (5) (4) Ground Y: (5) (4) Ground Z: (5) (4) Image X: (10) (8) Image Y: (10) (8) Fig-8 Ortho Resampling Setup Fig-9 Cross check wrt Google earth for Features matching C. Contour Generation A. 3D View Stereo Vision Fig-6 AT Summary Report Fig-10 Contour Generation Setup Fig-11 Contour Output 17

5 International Journal of Engineering and Technical Research (IJETR) V. CONCLUSION In this project work the suitability and the capability of Cartosat-1 data has been studied for the generation of Aerial Triangulation & Digital Elevation Model (DEM) Orthophoto: - Aerial photographs are not planimetric map, because they have geometric errors, those errors comes from tilt and relief displacement and when we correct the photos from those problems the result is orthophoto which is useful for 2D digitization. commonly used in Geographic Information Systems (GIS) as a "map accurate" background image The latest technique generating a contours is fast and less cost when comparing with manual surveying. Authors: Dr. S.S Manugula, Professor in GNITC, has B.Tech Civil Engineering (1994), M.Tech Remote Sensing (1998) through GATE qualified, and Ph.D. in Civil Engineering; He worked as a Research Assistant (projects) in IIT Mumbai in the department of CSRE. He has 23 years of experience (As a Civil Engg, GIS Photogrammetry-Remote Sensing) worked with National & International Clients in various multinational companies. He worked as a Dy. General Manager& Head of GIS department and also holds the credit of gaining global exposure by working in Abu-Dhabi (UAE) as a client side side support, international project work REFERENCES [1] Wolf, P.R. and Dewitt, B.A., Elements of Photogrammetry with Applications in GIS. 3rd Ed. McGraw-Hill. [2] Fritsch, D., Introduction into digital aerial triangulation. Photogrammetric week 95, Wichmann Verlag, pp [3] Grodecki, J., Dial, G., Block adjustment of high-resolution satellite images described by rational polynomials. Photogrammetric Engineering and remote sensing 69, pp [4] Jensen, J. R Introductory digital image processing: A remote sensing perspective. 2nd ed. Upper Saddle River, N.J.: Simon and Schuster. [5] Krzystek P., Heuchel T., Hirt U., Petran, An integral approach to automatic aerial triangulation and automatic DEM generaton, International archives of photogrammtery and remote sensing. Vol 31, part B3. Vienna 1996, [6] Morgan, M., K. Kim, S. Jeong, and A. Habib, Indirect Epipolar Resampling of Scenes Using Parallel Projection Modeling of Linear Array Scanners, XXth Congress of ISPRS, July, [7] Pablo d Angelo, Manfred Lehner, Thomas Krauss, Daniella Hoja and Peter Reinartz, Towards automated DEM generation from high resolution stereo satellite images, From web [8] Toni Schenk, Digital aerial triangulation, International archives of photogrammetry and remote sensing. Vol 31, part B3. Vienna 1996, [9] Tsingas, V. Operational use and empirical results of automatic aerial triangulation. Paper presented at the 45th Photogrammetric Week, WichmannVerlag, Karlsruhe, September 1995, [10] Yang, X., and D. Williams. The Effect of DEM Data Uncertainty on the Quality of Orthoimage Generation. Paper presented at Geographic Information Systems/Land Information Systems (GIS/LIAS) 97, Cincinnati, Ohio, October 1997, Mr. A Siva Sai Kumar, Student of GNITC, Final year B.Tech Civil Engineering. He is the CR (class representative), He placed in two Organisations through campus drive. He participated in Institute of Engineers, International Geospatial Form and also achieved 2nd Prize in paper/ project presentations in GNI colleges. Mr. B. Harish Goud, Student of GNITC, Final year B.Tech Civil Engineering., participated in Institute of Engineers, International Geospatial Form and also achieved 2nd Prize in paper/ project presentations in GNI colleges Mr. A. Rakesh, Student of GNITC, Final year B.Tech Civil Engineering. He participated in Institute of Engineers, International Geospatial Form and also achieved Prize in paper/ project presentations in various colleges 18